In Larry Niven's 'Ringworld' the explorers are always eating 'hand meals': for the longest time I resisted the obvious interpretation and imagined some unfathomable futuristic repast, but let's be honest - they're sandwiches aren't they.
Could also be a pasty! A British meal of basically <whatever you want> (typically meal and vegetables) wrapped in pastry, supposedly created so farm workers didn’t lose half their sandwiches when eating it.
Ha, indeed! To test this theory, next time I re-read the book I'm going to imagine Louis Wu speaking in a West Country accent throughout :)